Evaluation Of Water Resources Carrying Cpacity And Decision-making Of Scientific Coal Mining Scale In Northwest Mining Area Of China

Based on the characteristics of "rich coal reserve,deficient water and weak ecology" in the northwest mining area of China,this paper evaluates water resources carrying capacity(WRCC)in mining area and studies the determination method of mining scale under the constraint of water resources carrying capacity,with the purpose of solving the contradiction between coal mining and water resources protection in the northwest mining area of China.This study provides the basis for determining the scientific coal mining scale of large unmined coalfeild.Using methods such as theoretical analysis,numerical simulation,field demonstration and model deduction,this paper studies the concept definition of water resources carrying capacity in mining area under mining influence,presents the construction of evaluation system of water resources carrying capacity,and discusses the mining scale planning under the constraint of water resources carrying capacity.In addition,practical application is carried out by taking Yining mining area.The main research results are as follows:(1)Redefining the concept of water resource carrying capacity in mining area by taking mining influence as the entry point.Based on the change of water system stability under mining influence in the northwest mining area of China and its influence on the ecosystem,the concept of water resources carrying capacity based on mining principle is redefined from the broad sense and the narrow sense.Taking the water resources carrying capacity in the mining area as the "bridge",the evaluation of underground aquifer-protective mining technology and the rational determination of mining scale are realized simultaneously,and the connotation of aquifer-protective mining is expanded from underground mining control to surface ecological environment constraints.(2)The evaluation indicators system of water resources carring capacity in mining area under mining influence is constructed.According to the connotation and characteristics of the water resources carrying capacity in mining area and on the basis of the ecological environment stability in mining area during coal mining,the evaluation indicators system of water resource carrying capacity in mining area is constructed by taking geological system,mining system,water resource system and ecological system as the criterion layer and taking 11 indicators such as coal water occurrence relationship,mining parameters,aquifer water level change and water quality and quantity as the sub-criterion layer.According to the state response of water resource carrying capacity under mining action,the evaluation grade based on fuzzy comprehensive evaluation is given,and each evaluation grade is assigned with an evaluation value.(3)The influence rule of evaluation indicators is studied and the membership function of main indicators is determined.According to the basic situation of Yining mining area,a numerical analysis model with mining thickness and aquifuge layer position as variables is established.Based on theoretical analysis and simulation results,this paper studies the influence law of factors such as coal seam depth,mining parameters and groundwater level on water resources carrying capacity,determines the membership function of each indicators under mining influence,and obtains the weight of each influence factor.In addition,such model is applied to evaluate the state of water resources carrying capacity under the influence of mining in Yining mining area,and the reliability evaluation of underground aquifer-protective mining technology is realized.(4)The decision-making model of scientific coal mining scale based on water resources carrying capacity constraints is established,and the evaluation and decision system software is developed.By taking the water resources carrying capacity as the constraint condition and introducing the optimal control theory,the decision-making model of scientific coal mining scale is established by comprehensively considering the factors such as coal reserves,coal price,mining cost,market demand and additional cost induced by the decrease of water resources carrying capacity.Based on the VS platform,the software of "comprehensive decision-making system of water resources carrying capacity and mining scale" is designed and developed.Taking Yining mining area as an example,the determination method of mining scale is proposed based on water resources protection,the theory of aquiferprotective mining for large unmined coalfeild is innovated by controlling the mining source based on water resources carring capacity.